Rx7_fanofspeed

Hey Guys,
I have a 1986 FC NA.
I have spark and compression but no fuel.
My big question is will a Walbro 255 pump work with my S4 Fuel pressure regulator?
My buddy has had good luck with his 20b and the stock FPR.

Just wanted to get opinions on the issue. Fuel injectors were tested, cleaned and given a pass.

Thanks,

Tim..

Aaron Cake

iTrader: (1)

That Walbro will significantly increase fuel pressure, causing the car to run quite rich.

Just replace with a stock pump.

Have you actually tested the pump though? Jumper the yellow test connector at the passenger shock tower and turn the key to IGN. Does the pump run?

Rx7_fanofspeed

Hey Aaron thanks for getting back to me. Here is what my dad describes as the issue expands:

Subject: no fuel, bad voltage at fuel pump.
With ignition key on, no fuel coming out of fuel filter, nor noise from fuel pump with key on. With key on, and voltmeter grd to
blue/white wire in 4-pin fuel pump connector on fuel pump harness, I see 11.3vdc for about 3 seconds and then disappears. If
I repeat test and open connector, I see on blue/white wire 3.2 vdc and it too, disappears after 3 seconds. It's hard to blame fuel
pump if supply voltage is unstable like that. It seemed that maybe a fuel pump relay was bad? But I can't find any fuel pump
relay location to check.

Does the voltage disappearing at the connector suggest coditions somewhere aren't being met and it shuts down the fuel pump
voltage?

satch

iTrader: (1)

The pump will not run w/the key to on thus this is why Aaron told you to jumper the fuel check connector. It is located by the passenger strut tower and is Yellow encased in a Black rubber boot and is likely hidden underneath the Emission harness that runs to the side of the engine. The Pressure Sensor wires are from this Emission harness. The connector has two wires, one is Brown and the other is Black. Jumper these two wires together and w/key to on the pump should run. Try it, you'll like it.

Rx7_fanofspeed

Hey guys a update on the Car:
The problem we had was with the key on and the fuel filter hose opened, we had nothing from the fuel pump-no fuel at all. Thanks to the forum's guidance,
we jumpered the yellow connector at the passenger side front shock tower. We turned the key and had fuel delivery. Looks like the fuel pump is OK!

I then removed the connector jumper and turned on the key but had no fuel delivery. Since the jumper had bypassed the air flow sensor, it seemed that cranking
the engine would provide airflow to operate the A/F switch. It did and we had fuel pumping. Things started looking normal. Reconnecting the fuel filter hose,
we cranked again but although cranking, there was no combustion. I can't tell if the injectors are getting fuel or not. Can they be removed to watch for spray?

WE have good spark on the gaps of all 4 plugs and compression. Just no combustion. We don't smell raw fuel at the exhaust pipe. Any suggestions welcome. Thanks!

Aaron Cake

iTrader: (1)

You can listen to the injectors with a stethoscope or long screwdriver against your ear.

Or, pull the upper intake and remove the rail with injectors. Hold the injectors into the rail and have someone crank the car with the ignition coils unplugged. They should spray.